Jaime Biernaski

MMKV - Good bye AsyncStorage

Jaime Biernaski -

Almost every mobile application need to store some data locally for authetication of setup reasons. On React Native the way to go is (or used to be) using the AsyncStorage - storage system.

But performance was not the strengths of the AsyncStorage system! Now a new alternative (about 30x faster) is available for React Native derived from MMKV.

MMKV is an efficient, small, easy-to-use mobile key-value storage framework used in the WeChat application. It's currently available on Android, iOS/macOS, Win32 and POSIX.

The react-native-mmkv is a library that allows you to easily use MMKV inside your React Native applications. It provides fast and direct bindings to the native C++ library which are accessible through a simple JS API.

AsyncStorage vs MMKV: Reading a value from Storage 1000 times.Measured in milliseconds on an iPhone 8, lower is better.

Features

  • Get and set strings, booleans and numbers
  • Fully synchronous calls, no async/await, no Promises, no Bridge.
  • Encryption support (secure storage)
  • Multiple instances support (separate user-data with global data)
  • Customize storage location
  • High performance because everything is written in C++
  • ~30x faster than AsyncStorage
  • Uses JSI instead of the "old" Bridge
  • iOS, Android and Web support
  • Easy to use React Hooks API